Patent GB-1006113-A (GB)
Title: Improvements in or relating to the electro-photographic reproduction of images
IPC: G03G13/28
Filed: 1961-07-28
Abstract: An imagewise cathodic deposit of a porous hydroxide or hydrated oxide of one or more of Al, Ce, Mg, Mn or Mo is formed from an electrolyte solution of a soluble compound of one or more of these metals on an exposed photoconductive zinc oxide-in-resin layer or a contacting layer coated or impregnated with the electrolyte (see Division G2). Preferably the electrolyte has a concentration of 0.25-3.0% of the metal compounds and a voltage of 20-80 volts is applied between the conductive support of the zinc oxide layer as cathode and a second electrode separated from the layer by electrolyte.  If a porous deposit free from deposited metal is to be obtained the applied voltage should exceed 30 volts.  Examples are given of electrolyte solutions containing salts of Mg in combination with those of Ce, Mn, Fe, Co, or Ni and of a salt of Mn with a ferrous salt.  The deposit may be alkaline itself or may contain or be subsequently treated with alkaline or other reactive material, and may be used as the starting point in the production of coloured or colloid relief direct or transfer images, or printing surfaces (see Division G2). Specifications 1,006,114 and 1,006,116 are referred to.ALSO:High wet strength paper moistened with aqueous magnesium chloride solution is placed in contact with a conductivity image on an exposed zinc oxide-in-resin layer on an aluminium foil and a potential of 80 volts is applied between the foil as cathode and a roller electrode to deposit an alkaline pattern absorbed by the paper and a visible dark violet negative image is formed by swabbing the paper with an aqueous solution of 1-methyl-2 (21:41-dinitrobenzyl) pyridinium p-toluene sulphonate.  A baryta paper coated with a gelatin dispersion of the yellow dye 1-acetoxy-2[p-(b -hydroquinoylethyl) -phenylazo]-4-propoxynaphthalene and moistened with an aqueous magnesium salt solution yields a negative magenta image on the yellow dye background when a potential of 60 volts is applied through it between a backing positive electrode and the conducting support of an exposed zinc oxide-in-resin layer contacting the coated paper. Specification 1,006,114 and 1,006,116 are referred to.ALSO:Paper coated with polythene which may be pigmented with titanium dioxide is coated with a hardenable gelatin layer which also contains methyl violet; a black dye and optionally potassium nitrate and glycerol; cobalt nitrate and glycerol; Fe3O4 pigment and agar-agar, with or without potassium nitrate; or a water soluble dye and the ammonium salt of styrene-maleamic acid copolymer.  A similar polythene coated paper is coated with a softenable layer of gelatin containing a black dye and hardened with potassium alum or chromic chloride or with a layer of a gelatin binder containing indigo and a hardenable 2-vinyl pyridine copolymer.  A polyethylene terephthalate support is coated with an ethanol solution of hardenable methyl methacrylate-methacrylic acid.  To produce the hardening or softening these materials are brought into contact with porous alkaline hydroxide or hydrated oxide images which may contain other materials and have been produced by an electrolytic electrophotographic process (see Division G2).  Specifications 1,006,114 and 1,006,116 are referred to.